In the fiber optical communication technology to a higher and higher extent, in addition to loose or separate optical fibers, optical ribbon fibers or “ribbons” are used, i.e. optical fibers which by an outer enclosure are held to form a unit of type ribbon cable, i.e. a flat fiber assembly including a plurality of optical fibers extending in parallel to each other. Such ribbon fiber typically contains 2, 4, 6, 8, or 12 individual fibers.
When splicing optical fibers and ribbon fibers often fusion, also called welding or fusion welding, is used in devices particularly designed for this purpose. When splicing two different fibers to each other the different enclosures and protective layers are first removed. This can be made in a single step so that the naked surface of the optical fibers appears after the operation. Thereupon the naked fibers are cleaned, cut off, placed in the fiber-splicing device and are spliced to each other.
Thereafter a separate protective sleeve is placed over the splicing region. Such protective sleeves are usually heat-shrinkable pieces of tubing made of a suitable polymer material. Such a piece of tubing is then placed over the spliced portion of the fiber and the protective sleeve and the spliced portion is moved to a heating device, in which the protective sleeve is heated to make it shrink and tightly seal the spliced portion. The two operations, splicing using fusion and applying the protective sleeve tightly around the spliced portion, are most often executed in two separate devices but may equally well be executed in a single device with two operations, cf. WO 00/65388 OPTICAL FIBER SPLICING APPARATUS assigned to Telefonaktiebolaget LM Ericsson.
It is also possible to automate the process steps of stripping, cleaning, cutting, splicing through fusion, recoating and testing, through for instance robot technology. In this situation, each process step is a working station and a robotic arm moves each fiber between each station. All stations are working simultaneously wherefore the working time for the longest process step sets the limit for the speed of the total process. It is therefore important to minimise the time taken for each step. The time taken for splicing is approximately around 50 seconds. State of the art ovens or heating devices for recoating have difficulties with reaching these times and therefore constitutes a bottleneck in the process. It is of course also important to minimise each process step if an operator manually handles the fibers. Thus, the above process, described having a robot, can also be carried out with an operator moving the fiber between each process step.
These devices are also at times, in a mobile form, brought about to places where no mains is available, thus requiring their own power supply. Therefore, it is important to minimise power consumption.